Any conversation about Ohio State's national championship chances inevitably traces back to the Buckeyes' schedule.

The slate is the main reason why Urban Meyer's team sits at No. 3 in the BCS standings, despite a 9-0 record and a 21-game winning streak. It's also the reason why the Buckeyes soon could be behind a third unbeaten in Baylor, or even a 1-loss team in Stanford.

The Buckeyes have faced just one team in the current BCS standings, No. 22 Wisconsin. Barring a surprise, the only other ranked team they'll face before the BCS selections are announced will be in the Big Ten championship game.

How did this happen? Although Big Ten teams have shied away from tough schedules, Ohio State hasn't been one of them. In fact, the Buckeyes used a scheduling model that featured at least one marquee matchup per season, whether it was Texas in 2005 and 2006, USC in 2008 and 2009, or Miami in 2010 and 2011.

It's shortsighted to suggest, as many have, that Ohio State tried to avoid challenges in the schedule. For several reasons, the slate hasn't panned out, and it could keep Ohio State from playing for the crystal football.

Ohio State scheduled its home-and-home series with Cal in 2002. Thearon W. Henderson/Getty Images

Here's a closer look ...

1. The Cal series

Ironically, Ohio State's title hopes were impacted by a decision made in the Buckeyes' last championship season, 2002, when the school added a series with Cal. Scheduling games so far in advance is common, but it carries risks.

As Cal blossomed under Jeff Tedford from 2003-08, the series looked like a good one. But the Bears began declining in 2009. By the time the first game rolled around last fall, Cal was headed for a 3-9 campaign and a coaching change. The Bears, whom OSU defeated 52-34 on Sept. 14, are 1-9 this season.

"It just didn't work," Ohio State athletic director Gene Smith told ESPN.com. "You know, Cal had a run where they were rolling. Scheduling nonconference opponents is a little bit of art and a science. We have Oregon in the future, Oklahoma in the future, Texas in the future, TCU in the future. You hope that they stay great."

It would have been tough for Ohio State to back out of this year's return game at Cal, and even tougher to replace the Bears with a marquee foe.

"The only thing you could do is cancel it and take the financial hit that you pay in the penalty," Smith said. "But then you still have to find someone to fit that date. It's a supply-and-demand inventory issue, so sometimes the dates don't line up."

Ohio State replaced Vanderbilt with San Diego State, which went 9-4 in 2012 and shared the Mountain West championship. But the Aztecs struggled to a 0-3 start this fall before righting the ship.

According to Smith, the level of opponent and the Big Ten's scheduling moratorium during its short-lived scheduling pact with the Pac-12 also limited the options.

"There was really no one we could get, a major-major, to do a one-game [series]," Smith said. "We could have got some neutral-site games, but I can't take one of our games out of Columbus unless it's a huge [financial] number, and nobody can do that but Dallas."

AT&T Stadium in Arlington, Texas, hosts marquee season openers between major-conference teams, but was booked this year (LSU-TCU). Ohio State home games bring in $6.5 million for the athletic department, not to mention major gains for the Columbus community.

"The hotels, the restaurants, the taxi drivers, all those people count on those seven games a year," Smith said. "That's important to me. I have a social conscience. The neutral-site game has to be a big one."

So why is Ohio State's schedule criticized more? Because the Buckeyes receive little help from their conference.

The strength of the ACC and Big 12 -- real or perceived -- helps Florida State and Baylor. Some view the Pac-12 as the nation's strongest league, which could help one-loss Stanford leapfrog Ohio State. The Big Ten, meanwhile, remains a national piñata.

Michigan's struggles hurt. Northwestern, ranked 16th when Ohio State visited Evanston, is now in a five-game tailspin.

Even Ohio State's crossover schedule has been a detriment. The Buckeyes don't play 8-1 Michigan State, 8-2 Minnesota or 7-2 Nebraska during the regular season and will face only one in the Big Ten championship.

"We were hopeful," Smith said, "that the Big Ten would be a little stronger."

But he adds that perception is the biggest issue.

"Michigan State is one heck of a football team, Wisconsin is one heck of a football team," Smith said. "Just to dismiss our league says people haven't really looked at it. They haven't studied it. To dismiss our team means you haven't studied it."

Meyer didn't spent much time scrutinizing the schedule before the season, but he's aware of the Big Ten's perception problem.

"There's one way to eliminate all that talk: go win a bunch of bowl games and keep improving," Meyer said. "There's a lot of really good teams in our conference."

Still, it's hard to see the Big Ten helping the Buckeyes' chances. Ohio State needs help to get to Pasadena, Calif., on Jan. 6. The Buckeyes could be in Pasadena five days earlier for the 100th Rose Bowl game, which Smith calls "a heck of an accomplishment for our kids."

Ohio State likely won't have this problem in the future with marquee opponents lined up, and a nine-game league schedule beginning in 2016.

"You deal with what’s in front of you, because you can't control public opinion," Smith said.

"Still, at the end of the day, anybody who's won 20-plus games in a row, that's pretty strong."